1. Field of the Invention
The present invention relates to a terminal modified imide oligomer composition. More particularly, the present invention relates to a composition comprising an unsaturated imide compound and a terminal modified aromatic imide oligomer.
The terminal-modified imide oligomer composition of the present invention is easily fusible at a relatively low temperature and thus can be impregnated in a fiber material without using a solvent. Namely, the terminal-modified imide oligomer composition of the present invention is useful as a resinous material to be impregnated in a fiber material by a hot melt impregnating method for producing prepregs. The resultant prepregs are easily laminated on and bonded to each other by only light heating. The resultant prepregs are free from solvent and are thus safer than conventional solvent-containing prepregs. Also, the prepregs can be easily handled and are usable as a matrix for producing various composite materials. Also, the terminal-modified imide oligomer composition of the present invention is useful as a resinous material for producing various shaped articles and a hot melt binder.
2. Description of the Related Art
It is known that polyimide resin has a superior heat-resistance and thus is useful as a matrix resinous material for shaped resin articles and fiber-reinforced composite resin materials.
Recently, Japanese Unexamined Patent Publication (Kokai) Nos. 59-167,569, 60-250,030 and 60-260,624 disclose various addition reaction type polyimide resins (imide oligomers) which are reaction products of (a) pyromellitic dianhydride with (b) an aromatic diamine and (c) unsaturated reactive compound, have unsaturated terminal groups. These polyimide resins (imide oligomers) are usable as a resinous material for prepregs. A large number of these polyimide resins are, however, disadvantageous in low solubility in organic solvents, high difficulty in impregnation in reinforcing fiber material, and a high melting point which causes a resultant shaped article produced by a melt-shaping process to be heat-deteriorated.
Also, it is known that conventional imide oligomer resins have an unsatisfactory curing property, and thus need a long time for gelation thereof. Also, after curing, a certain amount of non-reacted curable groups remain in the resultant cured resin, and thus the cured resin does not exhibit a satisfactory mechanical strength. Also, when the conventional imide oligomer resins are used as a matrix resin for the preparation of prepregs, the conventional matrix resin exhibits an unsatisfactory affinity with reinforcing fibers and thus an interfacial separation easily occurs between the matrix resin and the reinforcing fibers. Various attempts have been made to solve the above-mentioned problems, and Japanese Unexamined Patent Publication (Kokai) Nos. 1-54,029, 1-54,030, 1-139,632, 1-247,430, 2-64,157, 2-64,136, 2-284,923, 3-174,427 and 4-363,360 disclose various inventions directed to terminal-modified imide oligomers.
Those terminal modified imide oligomers are successful in solving some of the above-mentioned problems. However, those oligomers are still disadvantageous in that they cannot be easily impregnated in a fiber material by a hot melt process, and thus the process for incorporating the terminal-modified imide oligomers into the fiber material is unsatisfactory even if the resultant composite material has a high heat-resistance.